1. Field of the Invention
The present invention relates to an improved structure of a perpetual calendar clock and, particularly, to an improved structure of a perpetual calendar clock in which a rotatory wheel set, flexible circuit boards, and driving apparatuses are used to generate intermittent signals and clock-control signals for driving a date wheel, a month wheel, and a day-of-the-week wheel to turn.
2. Description of the Prior Art
A common structure of a mechanical perpetual calendar usually requires numerous mechanically controlled components for connection and for control so that the date, the day of the week and the month displayed can be altered automatically. Such a structure has a disadvantageous large volume; also, the cost in its production cannot be lowered effectively. The perpetual calendar is thus under great competition pressure in the industry.
An improved structure of a conventional perpetual calendar clock comprises an outer case, rotatory wheels, a driving apparatus, a clock-control unit, and a battery set for supplying power. The outer case has a date window, a month window, a day-of-the-week window, and a clock window formed on the surface thereof. The outer case is hollow and contains the rotatory wheels, the driving apparatus, the clock-control unit and the battery set, which are all fixed within the outer case. The clock-control unit can trigger a signal for controlling the actuation of the driving apparatus. The driving apparatus is linked to a day-of-the-week wheel, a date wheel and a month wheel, which are circulated in sequence, and uses a contact surface of a substrate disposed therein for automatic alternation between those solar months without operation done by hand. The driving apparatus has a motor used for driving a gear set and the gear set controls a brake handle so that a brake switch generates signals. The driving apparatus comprises heavy means which occupy the most space and tend to have a linkage failure.
Since the convention has such drawbacks as described above, it is hardly a good one. An improvement is required urgently.
In view of the above difficulties associated with the conventional structure, the present inventor, through a long-term study and practice, has set about the work of improvement and innovation that provides the present improved structure of a perpetual calendar clock.